Federal regulators are softening a plan to oversee companies that trade financial derivatives, the complex investments that played a central role in the 2008 financial crisis.

The rule defines which companies trading derivatives will be subject to a stricter regime created in the 2010 overhaul of financial laws. Most companies that deal derivatives will be exempt.

The Securities and Exchange Commission and Commodity Futures Trading Commission approved the rule unanimously in separate votes Wednesday. The rule says derivatives used by companies to offset their own risk will not attract scrutiny. The higher oversight standard would apply only to companies that sell $8 billion or more of the investment products annually.

Under an earlier proposal, companies that sold $100 million of certain derivatives would have faced tougher oversight.